Method for manufacturing a tyre and apparatus for laying a reinforcing element on a forming support

ABSTRACT

An apparatus for the deposition of at least one reinforcing element on a forming including at least one feeding unit of at least one reinforcing element at a forming support, at least one deposition unit of the at least one reinforcing element on the forming support, the at least one deposition unit including at least one presser member, a control unit of the at least one deposition unit, at least one detection device of the deviations between an actual deposition profile and a theoretical deposition profile along a first deposition path defined based upon the theoretical profile, and a processing unit to define, based upon said deviations, an actual deposition path of the at least one reinforcing element on the forming support.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. application Ser. No.11/920,245, filed Mar. 4, 2009, now U.S. Pat. No. 8,262,822, which is anational phase entry under 35 U.S.C. §371 from PCT InternationalApplication No. PCT/IT2005/000307, filed May 30, 2005, the content ofwhich is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for manufacturing a tyre forvehicle wheels.

The invention also relates to an apparatus for the deposition of atleast one reinforcing element on a forming support, said apparatus beingable to be used to carry out the aforementioned method.

2. Description of the Related Art

Throughout the present description and the subsequent claims, the term“reinforcing element” is used to indicate an element comprising one ormore thread-like reinforcing elements, such as textile or metalliccords, incorporated in, or coated with, a layer of elastomeric material.

It should also be specified that, in the present description and in thesubsequent claims, the term “elastomeric material”, is used to indicatea composition comprising at least one elastomeric polymer and at leastone reinforcing filler. Preferably, such a composition also comprisesadditives such as, for example, a cross-linking agent and/or aplasticizer. Thanks to the provision of the cross-linking agent, such amaterial can be cross-linked through heating, so as to form the finalproduct.

A tyre for vehicle wheels generally comprises a carcass structurecomprising at least one carcass ply formed from reinforcing cordsincorporated in an elastomeric matrix. The carcass ply has end flapsrespectively engaged with annular anchoring structures arranged in thezones usually identified with the name “beads” and normally formed froma substantially circumferential annular insert on which at least onefilling insert is applied in a radially outer position. Such annularstructures are commonly identified as “bead cores”.

In a radially outer position with respect to the carcass ply, a beltstructure comprising one or more belt layers is associated, said beltlayers being arranged radially one on top of the other and havingtextile or metallic reinforcing cords orientated so that they crossand/or so that they are substantially parallel to the direction ofcircumferential extension of the tyre.

Between the carcass structure and the belt structure there may be alayer of elastomeric material, known as “under-belt”, having thefunction of making the radially outer surface of the carcass structureas uniform as possible for the subsequent application of the beltstructure.

In a radially outer position with respect to the belt structure a treadband is applied, also made of elastomeric material like other structuralelements forming the tyre.

Between the tread band and the belt structure a so-called “under-layer”made of elastomeric material with suitable properties to ensure a steadyunion of the tread band itself can be arranged.

On the side surfaces of the carcass structure, respective sidewalls madeof elastomeric material are also applied, each extending from one of theside edges of the tread band up to the respective annular structure foranchoring to the beads.

In “tubeless” tyres, the carcass ply is internally coated by a layer ofelastomeric material, preferably butylene-based, usually known as“liner”, having optimal characteristics of air impermeability andextending from one bead to the other.

Conventional manufacturing processes of tyres for vehicle wheelsessentially provide that the components of the tyre listed above befirstly made separately from each other and then are assembled in asubsequent tyre building step.

The current tendency is, however, that of using manufacturing processesthat allow the production and storage of semi-finished products to beminimised or, possibly, eliminated.

More specifically, attention has now turned towards process solutionsthat allow the individual components of the tyre to be made by directlyapplying them, according to a predetermined sequence, onto the tyrebeing built on a forming support, typically toroidal or cylindrical.

For example, in document WO 01/36185 to the same Applicant, thecomponents of the tyre are made on a toroidal support by sequentiallydepositing on the latter a plurality of reinforcing elements, consistingfor example of individual rubberised cords or of rubberized cordsgrouped in parallel in the form of strip-like elements, particularlyused in making the carcass and belt structure, and of continuouselongated elements made of elastomeric material, particularly used formaking the other structural components of the tyre, such as, forexample, tread band, sidewalls, liners, fillers.

It should be observed that in this case the manufacture of a tyreprovides for an automated process substantially without intermediatestorage of semi-finished products. In such a process the individualstructural components of the tyre described above are manufacturedaccording to a predetermined sequence starting from elongated elementsfed by a delivery member that can be operatively associated with anextruder. Thereafter, such elongated elements are deposited on theforming support by means of at least one presser member acting on theelongated element along a pressing direction and mobile with respect tothe forming support along a predetermined deposition path.

In patent EP 1 299 825 to the same Applicant, the design step of a tyreautomatically generates a plurality of procedures, which substantiallyreproduce the deposition sequences of all of the structural components,determined in the design step, with which the plant for the manufactureof tyres makes the new models thereof. Such procedures, preferably eachcontaining a deposition sequence of a structural element, are preferablylocated in a Data Base, from which they are suitably withdrawn to besent to a corresponding manufacturing unit of the production plant.

The Applicant has perceived that a method like that described in EP 1299 825 defines a priori the deposition path through software based upona theoretical deposition profile on which the deposition of theelongated element shall be carried out. In particular, such software,after having received in input a series of information identifying thetheoretical deposition profile, processes such information to calculatethe spatial coordinates of a series of points defining the depositionpath on the forming support.

In practice, the forming support on which the deposition of thereinforcing elements is carried out comprises, as well as the toroidalor cylindrical drum, a plurality of surface layers partially or totallyoverlapping and partially or totally consisting of elastomeric material.It results from this that, because of the dimensional tolerances of suchlayers, the actual deposition profile on which the deposition of thereinforcing element shall be carried out is different from thetheoretical one used to define the deposition path through theaforementioned software. This can cause a non-optimal deposition of thereinforcing elements on the forming support.

SUMMARY OF THE INVENTION

In particular, the Applicant has verified that the deposition of thereinforcing elements on the forming support along a deposition pathdefined from a theoretical deposition profile can cause defects on thetyre, such as overlapping or undesired spaces between contiguousreinforcing elements.

The Applicant has thus felt the need to develop a method and anapparatus that allows, in a manufacturing process of tyres like the onedescribed above, a deposition of the reinforcing elements to be carriedout based upon the actual deposition profile, so as to ensure an optimaldeposition and to thus ensure ever higher quality levels of the tyre.

The Applicant has found that this is possible by detecting thedeviations between actual deposition profile and theoretical depositionprofile along a first deposition path defined from a theoreticaldeposition profile and defining, based upon the detected deviations, anactual deposition path starting from the aforementioned first depositionpath.

The present invention therefore relates, in a first aspect thereof, to amethod for manufacturing a tyre for vehicle wheels, comprising the stepsof:

-   -   building a carcass structure, comprising at least one carcass        ply associated with annular anchoring structures, on a forming        support;    -   building a belt structure in a radially outer position with        respect to said carcass structure;    -   building a tread band in a radially outer position with respect        to said belt structure;

wherein said at least one carcass ply, said annular anchoring structuresand said belt structure each comprise at least one reinforcing element,deposited in a radially outer position with respect to said formingsupport;

wherein the deposition of at least one reinforcing element comprises thesteps of:

-   -   setting a first deposition path of said at least one reinforcing        element on said forming support based upon a theoretical        deposition profile;    -   detecting the deviations between an actual deposition profile        and said theoretical profile along said first deposition path;    -   defining, based upon said deviations, an actual deposition path        of said at least one reinforcing element on said forming        support;    -   depositing said at least one reinforcing element on said forming        support along said actual deposition path.

Advantageously, the method of the present invention allows a depositionof the reinforcing elements to be carried out on the forming supportalong an actual deposition path calculated based upon the actualdeposition profile determined starting from the profile of the formingsupport. Therefore, an optimal deposition of the reinforcing elements iscarried out, avoiding defects, such as overlapping or undesired spacesbetween contiguous reinforcing elements. In this way it is possible toensure high quality levels of the tyre.

In particular, in accordance with the present invention, the actualdeposition path is calculated, from a theoretical deposition path, basedupon the deviations detected between actual deposition profile andtheoretical deposition profile. Such deviations are due, for example, tothe dimensional tolerances of possible surface layers previouslydeposited on the forming support.

Preferably, the step of setting a first deposition path comprises thefollowing steps:

-   -   defining, through a calculation algorithm, said first deposition        path;    -   controlling at least one deposition unit of said at least one        reinforcing element to move at least one presser member of said        deposition unit in a predetermined position with respect to said        forming support, said predetermined position defining an initial        position of said first deposition path;    -   setting a detection device to zero.

Advantageously, the aforementioned first deposition path can be defineda priori through a calculation algorithm. In particular, this is asoftware that, having received in input a series of informationidentifying the theoretical deposition profile, processes suchinformation to calculate the spatial coordinates of a series of points.Such points define the theoretical deposition path.

In accordance with the present invention, the theoretical depositionpath is the path along which the deviations between actual depositionprofile and theoretical deposition profile are detected for thesubsequent definition of the actual deposition path.

Even more advantageously, in the method of the present invention thedetection device provides directly in output the deviations betweenactual deposition profile and theoretical deposition profile in virtueof the fact that it is set at zero before starting the detection step.

Preferably, in the aforementioned predetermined position said at leastone presser member generates a predetermined elongation of an elasticelement mechanically connected therewith. In such a way, said pressermember detects both possible positive deviations (caused, for example,by the fact that the thickness of the surface layers previouslydeposited on the forming support is, at one of the detection points,greater than the theoretical one) and possible negative deviations(caused, for example, by the fact that the thickness of the surfacelayers previously deposited on the forming support is, at one of thedetection points, lower than the theoretical one).

Preferably, said predetermined elongation is between about 2 mm andabout 5 mm.

Preferably, the step of detecting the deviations between actual profileand theoretical profile comprises the steps of:

-   -   moving said at least one presser member along said first        deposition path starting from, said predetermined position;    -   simultaneously detecting the deviations between actual profile        and theoretical profile in a pressing direction of said at least        one presser member on said forming support.

The detection of the deviations thus takes place whilst the pressermember travels the aforementioned first deposition path.

In a first embodiment of the method of the present invention, the stepof detecting the deviations between actual profile and theoreticalprofile is carried out in a setting step of the deposition cycle of saidat least one reinforcing element on said forming support. In such acase, advantageously, the actuation of the detection step does notinvolve any increase in the machine time necessary to carry out thedeposition cycle. This can be achieved, for example, in the depositionof the reinforcing elements to manufacture a belt layer of the tyre,where it is indeed foreseen that the deposition apparatus travels anidle cycle for initial setting.

In an alternative embodiment of the method of the present invention, thestep of detecting the deviations between actual profile and theoreticalprofile is carried out in a first deposition step of a deposition cycleof said at least one reinforcing element on said forming support. Thiscan be achieved, for example, in the deposition of the reinforcingelements for manufacturing the carcass plies of the tyre or in thedeposition of the bead cores for manufacturing the anchoring structuresof the carcass structure.

In a preferred embodiment of the method of the present invention, thestep of defining an actual deposition path comprises the step ofcorrecting said first deposition path based upon said deviations.

Advantageously, the calculation of the actual deposition path thus takesplace only in the case in which deviations between actual profile andtheoretical profile are detected. Even more advantageously, such acalculation simply provides for the correction of the coordinates ofonly those points of the first deposition path at which the deviationsbetween actual profile and theoretical profile have been detected. Thisadvantageously allows the computing burden required for defining theactual deposition path to be reduced to the minimum.

Preferably, the step of correcting said first deposition path is carriedout only if said deviations are outside of a predetermined tolerancerange. This allows the computing burden required for defining the actualdeposition path to be further limited.

Preferably, said predetermined tolerance range is between about −1.5 mmand about +1.5 mm, more preferably between about −0.5 mm and about +0.5mm.

In the preferred embodiment of the method of the present invention, theaforementioned forming support is a toroidal drum. Alternatively, theforming support can be a cylindrical support. Such a shape of thesupport can be useful for making some structural components of the tyre(like the belt structure or the tread band) in manufacturing processesof tyres that provides for manufacturing the different structuralcomponents of the tyre separately on many forming supports and theirsubsequent assembly to obtain the finished tyre.

Irrespective of the specific type of the forming support, preferably, itcomprises one or more surface layers of elastomeric material previouslydeposited. In such a case, because of the large dimensional tolerancesof the elastomeric material, it is absolutely probable that the actualdeposition profile is different to the theoretical one. Advantageously,the method of the present invention allows optimal deposition of thereinforcing elements to also be carried out in such a circumstance.

Preferably, the aforementioned first deposition path extends along adeposition direction having at least one component parallel to arotation axis of said forming support. In other words, the method of theinvention is preferably used in the cases in which the reinforcingelements are deposited on the surface of the forming support accordingto a predetermined deposition angle with respect to a direction ofcircumferential development of the forming support itself, like forexample in manufacturing the belt and/or carcass structure of the tyreand of the bead cores for the anchoring of the carcass structure.

In an embodiment of the method of the present invention, said at leastone reinforcing element is applied onto said forming support in the formof a plurality of pieces of predetermined length cut from an element fedsubstantially continuously at said forming support. This is the case,for example, of the deposition of the reinforcing elements formanufacturing a belt layer of the tyre or for the manufacture of acarcass ply.

In an alternative embodiment of the method of the present invention,said at least one reinforcing element is applied onto said formingsupport in the form of a substantially continuous element. This is thecase, for example, of the deposition of the bead cores for manufacturingthe anchoring structures of the carcass structure.

In a second aspect thereof, the present invention relates to anapparatus for the deposition of at least one reinforcing element on aforming support, comprising:

-   -   at least one feeding unit of at least one reinforcing element at        a forming support;    -   at least one deposition unit of said at least one reinforcing        element on said forming support, said at least one deposition        unit comprising at least one presser member;    -   a control unit of said at least one deposition unit;    -   at least one detection device of the deviations between an        actual deposition profile and a theoretical deposition profile        along a first deposition path defined based upon said        theoretical profile;    -   a processing unit to define an actual deposition path of said at        least one reinforcing element on said forming support based upon        said deviations.

Such an apparatus can advantageously be used to carry out the method ofthe present invention described above.

In a first embodiment of the apparatus of the present invention, said atleast one detection device comprises at least one electromechanicalposition sensor.

In a second embodiment of the apparatus of the present invention, saidat least one detection device comprises at least one optical positionsensor.

Preferably, said at least one detection device is integrally associatedwith a frame of said apparatus and is active on said at least onedeposition member to detect the displacements of said at least onepresser member along a predetermined pressing direction.

In a further preferred embodiment, the apparatus of the presentinvention also comprises a cutting member to cut a plurality of piecesof predetermined length of said at least one reinforcing element on saidforming support from at least one substantially continuous element andat least two presser members that are mobile away from each other toapply said pieces on said forming support.

Preferably, in such an embodiment of the apparatus of the presentinvention said at least two presser members are rolling presser members.

Such an embodiment is used, for example, in the deposition of thereinforcing elements for manufacturing a belt layer of the tyre and/orin the deposition of the reinforcing elements for manufacturing carcassplies of the tyre.

In a different preferred embodiment, said at least one reinforcingelement is applied on said forming support in the form of asubstantially continuous element.

Such an embodiment is used, for example, in the deposition of the beadcores for manufacturing the anchoring structures of the carcassstructure.

In the preferred embodiments of the apparatus of the present invention,said forming support is a toroidal or cylindrical drum that, preferably,comprises one or more surface layers of elastomeric material previouslydeposited.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention shallbecome clearer from the following detailed description of a preferredembodiment of an apparatus and of a method in accordance with thepresent invention, made with reference to the attached drawings. In suchdrawings:

FIG. 1 schematically shows an embodiment of the apparatus according tothe present invention in an operating step of the deposition cycle ofthe reinforcing elements on the forming support;

FIG. 2 schematically shows the apparatus of FIG. 1 in an operating stepsubsequent to that of FIG. 1.

DETAILED DESSCRIPTION OF THE INVENTION

In FIG. 1, an example embodiment of an apparatus for making reinforcingstructures for vehicle tyres in accordance with the present invention iswholly indicated with 1.

The apparatus 1 is part of a work station of the type described indocument WO 01/36185 to the same Applicant.

In the described embodiment, the apparatus 1 is suitable formanufacturing a belt structure on a toroidal support 3 having an outersurface 3 a substantially configured according to the internalconfiguration of the tyre to be obtained. The toroidal support 3 is notdescribed in detail since it can be made in whatever suitable way by theman skilled in the art.

In the aforementioned embodiment, the reinforcing elements preferablyconsist of pieces 5 of predetermined length obtained through cuttingoperations carried out sequentially on at least one continuousstrip-like element 6 coming from a drawing and/or calandering device, orfrom a feed reel. The continuous strip-like element 6, and consequentlythe pieces 5 obtained from it, each have a plurality of cords or similarmade of metal or textile material, extending parallel to each otheralong the longitudinal extension of the strip-like element 6 and of thepiece 5 itself, and they are at least partially coated by a layer ofelastomeric material applied through a drawing and/or calanderingoperation.

It should be specified that, if needed, the apparatus 1 as well as themethod carried out by it are also suitable for being used to make otherreinforcing structures of the tyre, like for example the carcassstructure.

In an alternative embodiment thereof that is not illustrated, theapparatus 1 of the present invention is used for the deposition of thebead cores for manufacturing the anchoring structures of the carcassstructure. In such a case, the reinforcing elements preferably consistof a cord of metal or textile material coated with a layer ofelastomeric material, hereafter known as rubberized cord. Such arubberized cord is fed at the tyre in the form of a continuous elementand is deposited at the bead of the tyre according to a substantiallyspiral progression through the action of a presser member suitablyprovided.

In the embodiment illustrated in the attached figures, before making thebelt structure, a carcass structure (not illustrated in the drawings) ispreferably built on the toroidal support 3. Such a structure canadvantageously be formed on the toroidal support 3 for example accordingto what is described in patent EP 0 928 680 to the same Applicant.

One or more surface layers of entirely elastomeric material or materialcomprising one or more reinforcing elements incorporated in, or coatedwith, elastomeric material can have been built on the toroidal support3, in addition to the carcass structure.

The apparatus 1 comprises a frame 2, schematically represented in theattached figures, on which at least one feed unit 4 is mounted, saidfeed unit being arranged to provide the strip-like pieces 5 ofpredetermined length from the continuous strip-like element 6.

The feed unit 4, in turn, comprises at least one cutting member 7arranged to cut the continuous strip-like element perpendicularly oraccording to a predetermined inclination with respect to thelongitudinal extension thereof, to obtain the individual strip-likepieces 5. At least one gripping member (not illustrated) that is mobilebetween a first work position in which it is intended to engage aterminal end 6 a of the continuous strip-like element 6 at the cuttingmember 7, and a second work position in which it is positioned away fromthe cutting member itself, is combined with the cutting member 7.Following the translation from the first to the second work position,the gripping member drags the continuous strip-like element 6 so as tolay it beyond the cutting member 7 and preferably in a position radiallyclose to the toroidal support 3, according to a portion of lengthcorresponding to that of the strip-like piece 5 to be obtained followingthe subsequent actuation of the cutting member itself. Preferably, apair of rollers, indicated with 9 in FIG. 1, operate on the continuousstrip-like element 6 in a zone immediately upstream of the cuttingmember 7 to guide such a continuous strip-like element 6 towards such acutting member 7.

The apparatus 1 further comprises at least one deposition unit 10schematically represented in the attached figures, which is intended tosequentially engage each of the strip-like pieces 5 prepared in the waydescribed previously, to deposit them on the outer surface 3 a of thetoroidal support 3.

Preferably, the deposition unit 10 comprises at least one presser member11 that is mobile along the strip-like piece 5, in contrastingrelationship against the outer surface 3 a of the toroidal support 3.More specifically, in a preferred embodiment at least two rollingpresser members 11 are used, each carried by a support element 12 thatis mobile along a guide structure 13 upon the action of transversalmoving devices, for example of the worm screw type, not illustratedsince they can be made by the man skilled in the art in whateverconvenient way.

An elastic element (not illustrated), having its own constant elasticityk is associated with each presser member 11, said elastic elementpreferably being a spring. When the presser members 11 are pressedagainst the outer surface 3 a of the toroidal support 3 with apredetermined force F, a predetermined elongation of the spring equal toF/k is generated. Preferably, the elasticity constant k and the setforce F are selected so that the aforementioned elongation is betweenabout 2 mm and about 5 mm.

At least one auxiliary holding element 14, that is suitable forcooperating with the respective presser member 11 to hold the strip-likepiece 5 in the time between the cutting of the latter upon the action ofthe cutting member 7 and the application onto the toroidal support 3, isalso preferably associated with each support element 12. In greaterdetail, each auxiliary holding element 14 can for example consist of asmall roller projecting from the respective support element 12 so as toprovide a support seat for the elongated element 6 dragged by thegripping member and for the cut strip-like piece 5.

Radial moving devices, provided to translate the presser members 11radially closer to the outer surface 3 a of the toroidal support 3, arealso associated with the deposition unit 10. Such radial moving devicesare neither illustrated nor described in detail since they can be madein any way suitable for the man skilled in the art, and can for exampleoperate on the guide structure 13 and/or directly on the presser members11, in order to take the strip-like piece 5 in contact relationship onthe outer surface 3 a of the toroidal support 3.

Transversal moving devices are also provided, also not illustrated sincethey can be made in any suitable way, operating for example between theguide structure 13 and the blocks 12 to translate the presser members 11between a first operating condition in which, according to FIG. 1, theyare close together and a second operating condition in which, accordingto FIG. 2, they are moved apart with respect to an equatorial plane Y-Yof the toroidal support 3.

The apparatus 1 further comprises a control unit (not illustrated) tocontrol the movement of the deposition unit 10 with respect to thetoroidal support 3 and the movement of the presser members 11 from thefirst operating position, illustrated in FIG. 1, to the second operatingposition, illustrated in FIG. 2 along a predetermined deposition path.

Further details of the apparatus 1 and the preparation and depositionmethods of each strip-like piece 5 on the toroidal support 3 are forexample described in patent EP 1 147 007 to the same Applicant.

The Applicant has found that, in the absence of further provisions thatshall be described hereafter, the deposition of the strip-like pieces 5with an apparatus 1 of the type described above could not take place inan optimal manner.

Indeed, it should be specified that the deposition path is defined apriori through software based upon a theoretical deposition profile fromthe profile of the toroidal support 3. In particular, such software,having received a series of information identifying the theoreticaldeposition profile in input, processes such information to calculate thespatial coordinates of a series of points that define the depositionpath.

Since in practice the actual deposition profile is different from thetheoretical one, the deposition of the strip-like pieces 5 on thetoroidal support 3 may not be optimal.

The Applicant has therefore implemented some provisions suitable forallowing the deposition of the strip-like pieces 5 on the toroidalsupport 3 to take place along a deposition path calculated based uponthe actual deposition profile, for example corresponding to the profileof the toroidal support 3 supporting other structural components of thetyre being processed, for example liner, carcass ply/plies, bead cores,under-belt.

In accordance with the present invention, the apparatus 1 furthercomprises a detection device 20 suitable for detecting the deviationsbetween the actual deposition profile and the theoretical depositionprofile along the deposition path defined a priori based upon thetheoretical deposition profile. The apparatus 1 also comprises aprocessing unit suitable for processing an actual deposition path of thestrip-like pieces 5 on the toroidal support 3, based upon the detecteddeviations.

In its preferred embodiment, the detection device 20 is anelectromechanical or optical position sensor. Such a sensor isintegrally associated with the frame 2 of the apparatus and is active onthe deposition unit 10 to detect the displacements of the pressermembers 11 along a predetermined pressing direction P. For such apurpose, the detection device 20 is associated with the frame 2 throughthe interposition of a conventional elastic element 21, for example aspring.

In the attached figures, the detection device 20 is positioned at theinterface between the frame 2 and the deposition unit 10 so as tooperate on the deposition unit 10. In such a configuration the pressermembers 11 are assumed to be integral, in the movement along thepressing direction P, with the other members of the deposition unit 10,i.e. that the displacements of the presser members 11 during themovement of these presser members 11 along the pressing direction P fromthe first operating position, illustrated in FIG. 1, to the secondoperating position, illustrated in FIG. 2, carry out into correspondingdisplacements of the entire deposition unit 10. The man skilled in theart shall understand that the position of the detection device 20 can inany case be different to the one represented. In particular, thedetection device 20 can be positioned so as to act directly on thepresser members 11 or on any other member of the deposition unit 10,provided that such a member is integral with the presser members 11 inthe movement of these presser members along the pressing direction P.

The detection device 10, whenever a deviation between the actualdeposition profile and the theoretical deposition profile is detected,generates an electrical signal representative of such deviations. Suchan electric signal is sent to the processing unit that, based upon sucha signal, corrects the spatial coordinates of those points of thetheoretical deposition path at which the deviations have occurred.

As already stated, the apparatus 1 described above can be used for thedeposition of the strip-like pieces 5 on the toroidal support 3 formanufacturing a belt structure of a tyre in a method for manufacturing atyre for vehicle wheels.

Such a method initially comprises the step of building, on the toroidalsupport 3 a, a carcass structure comprising at least one carcass ply.After such a step, it is carried out the step of building the beltstructure in a radially outer position with respect to the carcassstructure and thereafter it is carried out the step of building a treadband in a radially outer position with respect to the belt structure.

The steps of building the carcass structure and/or the belt structurecomprise a deposition step of a plurality of strip-like pieces 5 on theouter surface 3 a of the toroidal support 3. Such a step initiallyprovides for the definition of a theoretical deposition path based uponthe theoretical deposition profile.

As already stated, the theoretical deposition path is calculated througha calculation algorithm that, based upon a series of identifyinginformation of a theoretical toroidal support and of the tyre to bebuilt, calculates the spatial coordinates of a series of points definingthe aforementioned theoretical deposition path.

Thereafter, the control unit acts upon the deposition unit to move thepresser members 11 into a predetermined position in contact on thetoroidal support 3. Such a position defines an initial position of thetheoretical deposition path. In this step, the detection device is setat zero.

Thereafter, the presser members 11 are moved along the theoreticaldeposition path to carry out an initial setting cycle of the machine. Atthe same time as such a displacement, the detection device detects thedeviations between theoretical deposition profile and actual depositionprofile along a predetermined pressing direction P and generates anelectric signal representative of such deviations. Such a signal is sentto the processing unit, which then provides for correcting the spatialcoordinates of those points of the theoretical deposition path in whichthe deviations have occurred.

An actual deposition path is thus defined.

In the preferred embodiment of the method of the present invention, thecorrection of the spatial coordinates of the theoretical deposition pathis carried out only if the detected deviations are outside apredetermined tolerance range, for example between about −1.5 mm andabout +1.5 mm, preferably between about −0.5 mm and about +0.5 mm.

At this point the actual deposition step of the strip-like pieces 5begins. In such a step, the control unit provides for moving the pressermembers 11 along the actual deposition path calculated previously.

In the case of the deposition of the bead cores to make an anchoringstructure of the carcass structure, a rubberized cord preferablyconsisting of a thread-like element made of metal or textile materialcoated with a layer of elastomeric material is fed at the toroidalsupport 3. Such a rubber cord is fed at the tyre in the form of acontinuous element and is deposited at the bead of the tyre according toa substantially spiralling progression through the action of a suitablyprovided presser member.

The first deposition cycle (corresponding to the first turn of thespiralling path) is carried out based upon the theoretical depositionpath calculated a priori in the way described above. Whilst such a cycleis being carried out the deviations between actual deposition profileand theoretical deposition profile are detected.

Thereafter, the steps of correction of the theoretical deposition pathand of actual deposition are carried out according to what isillustrated above.

What is claimed is:
 1. An apparatus for the deposition of at least onereinforcing element on a forming support, comprising: at least onefeeding unit of at least one reinforcing element at a forming support;at least one deposition unit of said at least one reinforcing element onsaid forming support, said at least one deposition unit comprising atleast one presser member; a control unit of said at least one depositionunit; at least one detection device of the deviations between an actualdeposition profile and a theoretical deposition profile along a firstdeposition path defined based upon said theoretical profile; and aprocessing unit to define, based upon said deviations, an actualdeposition path of said at least one reinforcing element on said formingsupport; wherein the control units controls the at least one pressermember to move with respect to the forming support along the firstdeposition path to carry out an initial setting cycle of the apparatusprior to commencing deposition of the at least one reinforcing elementand along the actual deposition path for depositing the at least onereinforcing element.
 2. The apparatus according to claim 1, wherein saidat least one detection device comprises at least one electromechanicalposition sensor.
 3. The apparatus according to claim 1, wherein said atleast one detection device comprises at least one optical positionsensor.
 4. The apparatus according to claim 1, wherein said at least onedetection device is integrally associated with a frame of said apparatusand is active on said at least one deposition unit to detect thedisplacements of said at least one presser member along a predeterminedpressing direction.
 5. The apparatus according to claim 1, furthercomprising a cutting member to cut a plurality of pieces ofpredetermined length of said at least one reinforcing element on saidforming support from at least one substantially continuous element; andwherein at least two presser members comprises at least two pressermembers that are mobile away from each other to apply said pieces onsaid forming support.
 6. The apparatus according to claim 5, whereinsaid at least two presser members are rolling presser members.
 7. Theapparatus according to claim 1, wherein said forming support is atoroidal drum.
 8. The apparatus according to claim 1, wherein saidforming support is a cylindrical drum.
 9. An apparatus for thedeposition of at least one reinforcing element on a forming support, theapparatus comprising: at least one feeding unit of at least onereinforcing element at a forming support; at least one deposition unitof said at least one reinforcing element on said forming support, saidat least one deposition unit comprising at least one presser member; acontrol unit of said at least one deposition unit; at least onedetection device of the deviations between an actual deposition profileand a theoretical deposition profile along a first deposition pathdefined based upon said theoretical profile; and a processing unit todefine, based upon said deviations, an actual deposition path of said atleast one reinforcing element on said forming support; wherein the atleast one presser member is configured to move with respect to thedetection device from a first position to a second position along theactual deposition path.
 10. The apparatus according to claim 9, whereinsaid at least one detection device comprises at least oneelectromechanical position sensor.
 11. The apparatus according to claim9, wherein said at least one detection device comprises at least oneoptical position sensor.
 12. The apparatus according to claim 9, whereinsaid at least one detection device is integrally associated with a frameof said apparatus and is active on said at least one deposition unit todetect the displacements of said at least one presser member along apredetermined pressing direction.
 13. The apparatus according to claim9, further comprising a cutting member to cut a plurality of pieces ofpredetermined length of said at least one reinforcing element on saidforming support from at least one substantially continuous element; andwherein the at least one presser member comprises at least two pressermembers that are mobile away from each other to apply said pieces onsaid forming support.
 14. The apparatus according to claim 13, whereinsaid at least two presser members are rolling presser members.
 15. Theapparatus according to claim 9, wherein said forming support is atoroidal drum.
 16. The apparatus according to claim 9, wherein saidforming support is a cylindrical drum.